EMG Flashcards
Describe Electromyography- with a focus on noninvasive techniques
Discuss the merits of needling vs surface recording techniques
Discuss EMG and Behaviour: performance and reaction time
Davis (1940) recorded EMG from forearm extensor muscles while subject waited for signal requiring response. Muscle tension began 200-400 msec after signal. RT was faster the higher initial muscle tension was ( RT was quicker and muscle tension higher for periods vs irregular periods)
Kennedy and Travis (1948) looking at tracking from frontalis muscle showed that RT become slower with low levels of tension and faster with high tension level
Non involved muscles show low EMG activity- this is linked with decreases in HR ( cardiac- somatic concept)
Tracking: Discuss EMG and Behaviour
Tracking- movement of control to indicate moving target. I.e. video games and pilots
Efficient tracking= related to moderate to high EMG level. Low muscular tension ( indicate drowsiness), or high ( overexertion/fatigue) are associated with less efficient performance
Practice= improves tracking. Simple repetition without fatigue improves performance
Motivation= facilitates performance. Fatigue hinders it (Eason and White). Fatigue causes integrated EMG levels to increase but muscle efficiency to decrease
Speech: Discuss EMG and Behaviour
Oral EMGs occur during thinking ( not confined to larynx). Speech muscles are separate ( Goldestein 1972): “muscle activity accompanies all cognitive phenomena, even though EMG may be of small magnitude” (McGuigan 2973)
Sub vocalisation during reading limits reading rate to 150 words/min, Hardyck et al (1966) found 17/50 subjects were sub vocalisers
Audio EMG feedback of laryngeal muscles *- within 30 min. All able to read with EMG at resting levels. Reductions in reading fatigue occurred.
Mcguigan (1973) in a contrasting view suggested that higher levels of oral EMG in children and less proficient adults enhances comprehension levels, and reduces distractions in noisy environment
Performance:Discuss EMG and Behaviour
Max effort can be maintained only 1 min. 25% of max for approx. 10 min. Efficiency decreases when high level of exertion required
Maintaining performance under fatigue requires more energy ( higher level of EMG). 20min pencil paper test doing addition problem
Normal sleep vs 32-56 hr sleep deprivation
After sleep loss, EMG from inactive forearm show those with greatest increases in EMG over normal levels, performed best (Wilkinson 1962)
Desk slant position (Eastman and Kamon, 1976)
EMG was recorded from deltoid, trapezius and spinae erector (lower back ) while subjects performed reading and writing tasks at 12 and 24 degree desk tlits. Work stations can therefore be redesigned
Mental activity: Discuss EMG and Behaviour
Emotion: Discuss EMG and Behaviour
Myasthenia Gravis
Parkinsons
Lower Back Pain & Pelvic Floor Muscle tone
Difference between Myasthenia gravis and repetitive strain injury
EMG & Pathophysiology including stuttering
EMG & Pathophysiology including Behaviour and emotion,
Rheumatoid Arthritis
